The present invention relates to the scheduling the movement of plural trains through a rail network, and more specifically, to the scheduling of the movement of trains over a railroad system utilizing the pre-allocation of resources.
Systems and methods for scheduling the movement of trains over a rail network have been described in U.S. Pat. Nos. 6,154,735, 5,794,172, and 5,623,413, the disclosure of which is hereby incorporated by reference.
As disclosed in the referenced patents and applications, the complete disclosure of which is hereby incorporated herein by reference, railroads consist of three primary components (1) a rail infrastructure, including track, switches, a communications system and a control system; (2) rolling stock, including locomotives and cars; and, (3) personnel (or crew) that operate and maintain the railway. Generally, each of these components are employed by the use of a high level schedule which assigns people, locomotives, and cars to the various sections of track and allows them to move over that track in a manner that avoids collisions and permits the railway system to deliver goods to various destinations.
As disclosed in the referenced patents and applications, a precision control system includes the use of an optimizing scheduler that will schedule all aspects of the rail system, taking into account the laws of physics, the policies of the railroad, the work rules of the personnel, the actual contractual terms of the contracts to the various customers and any boundary conditions or constraints which govern the possible solution or schedule such as passenger traffic, hours of operation of some of the facilities, track maintenance, work rules, etc. The combination of boundary conditions together with a figure of merit for each activity will result in a schedule which maximizes some figure of merit such as overall system cost.
As disclosed in the referenced patents and applications, and upon determining a schedule, a movement plan may be created using the very fine grain structure necessary to actually control the movement of the train. Such fine grain structure may include assignment of personnel by name, as well as the assignment of specific locomotives by number, and may include the determination of the precise time or distance over time for the movement of the trains across the rail network and all the details of train handling, power levels, curves, grades, track topography, wind and weather conditions. This movement plan may be used to guide the manual dispatching of trains and controlling of track forces, or may be provided to the locomotives so that it can be implemented by the engineer or automatically by switchable actuation on the locomotive.
The planning system is hierarchical in nature in which the problem is abstracted to a relatively high level for the initial optimization process, and then the resulting coarse solution is mapped to a less abstract lower level for further optimization. Statistical processing is used at all levels to minimize the total computational load, making the overall process computationally feasible to implement. An expert system is used as a manager over these processes, and the expert system is also the tool by which various boundary conditions and constraints for the solution set are established. The use of an expert system in this capacity permits the user to supply the rules to be placed in the solution process.
Currently, the movements of trains are typically controlled in a gross sense by a dispatcher, but the actual control of the train is left to the crew operating the train. Because compliance with the schedule is, in large part, the prerogative of the crew, it is difficult to maintain a very precise schedule. As a result it is estimated that the average utilization of these capital assets in the United States is less than 50%. If a better utilization of these capital assets can be attained, the overall cost effectiveness of the rail system will accordingly increase.
Another reason that the train schedules have not heretofore been very precise is that it has been difficult to account for the factors that affect the movement of trains when setting up a schedule. These difficulties include the complexities of including in the schedule the determination of the effects of physical limits of power and mass, speed limits, the limits due to the signaling system and the limits due to safe handling practices, which include those practices associated with applying power and braking in such a manner to avoid instability of the train structure and hence derailments. One factor that has been consistently overlooked in the scheduling of trains is the effect of the behavior of a specific crew on the performance of the movement of a train.
As more use is made of a railroad system, the return on infrastructure will be enhanced. Greater rail traffic will, however, lead to greater congestion and present dispatching systems will be strained and eventually incapable of handling the desired extra traffic load. The problem is further complicated by the impending necessity for an efficient transfer from a manual dispatch system to an automated dispatch system. There is therefore a need to devise new control strategies for more efficient dispatch procedures and concomitantly greater operating efficiencies of a railroad.
The present application is directed to planning the movement of trains through the use of virtual consists to achieve a more stable and efficient use of planning resources.
These and many other objects and advantages of the present disclosure will be readily apparent to one skilled in the art to which the disclosure pertains from a perusal of the claims, the appended drawings, and the following detailed description of the embodiments.